Conventionally known membrane separation devices include, for example, a technology shown in FIG. 20. In the technology, a membrane module 1 includes a plurality of membrane elements 2 arranged in parallel to one another and having a predetermined distance therebetween, a flow channel for water to be treated formed in a longitudinal direction thorough the membrane elements 2, and collecting cases 3 provided on both sides of the membrane elements 2. Each of the collecting cases 3 is provided, inside thereof, with a hollow space for collecting water, and filtrate passed through each membrane element 2 is collected in the water collecting space. A resin 4 is filled between the membrane elements 2 being adjacent to one another, and between the membrane elements 2 and the collecting cases 3. The plurality of membrane elements 2 are integrated and attached to the collecting cases 3 with watertight sealing by use of the resin 4. The filtrate collected in the collecting cases 3 is vacuum-discharged outside through discharge outlets 5 provided on the upper end surfaces of the collecting cases 3.
A technology disclosed in Japanese Patent Laid-open Publication No. 11-33370 includes a plurality of filtration membrane bodies that are provided in parallel to one another and integrated at both sides thereof, and a filtrate collecting portion that is provided at each of the integrated sides of the filtration membrane bodies and communicating with the inside of each filtration membrane body. Each filtration membrane body has two flat membranes laminated with a spacer therebetween. Two ends of one flat membrane are attached and sealed to two ends of the other flat membrane.
Another technology is disclosed in Japanese Patent No. 32932159, in which a plurality of unit modules are arranged with a predetermined distance therebetween, and left and right sides of each unit module are fixed to a housing. Each unit module is configured with a membrane provided at both sides of a spacer. Upper and bottom edges of the unit module are fixed and sealed with an adhesive. A connecting portion between the unit modules and the housing are also fixed and sealed with a sealer or a filler. Thereby, an unfiltered liquid is prevented from entering a filtrate chamber and a collecting chamber.